Construction\nof Vine-Inspired\nAntimicrobial Filter\nwith Multiscale 3D Nanonetwork for High-Efficiency Air Filtration

Enhancing the antimicrobial activity\nof high-efficiency\nparticulate\nair (HEPA) filters while maintaining filtration efficiency and pressure\ndrop is currently an urgent issue for preventing the spread of pathogenic\nmicroorganisms. Herein, inspired by vines which can enwind fences\nto fix as well as decorate them, a flexible antimicrobial chitin nanofiber\n(ChNF@CuO<i><sub>x</sub></i>) was fabricated and loaded\nonto the rigid glass fiber (GF) skeleton of a HEPA filter. Through\nthe physical interaction, ChNF@CuO<sub><i>x</i></sub> was\nspontaneously enwound on GF, and ChNF@CuO<sub><i>x</i></sub> itself interweaved to form a new nanonetwork between the GF skeleton.\nThe obtained antimicrobial air filter (ChNF@CuO<sub><i>x</i></sub>/GF) with a unique nanonetwork increased the filtration efficiency\nof the HEPA filter. Meanwhile, it possessed excellent inactivation\nability against <i>Staphylococcus aureus</i>, <i>Escherichia\ncoli</i>, and <i>Candida albicans</i> due to the urchin-like\nin situ grown CuO<sub><i>x</i></sub> on the ChNF. In particular,\nthe oxygen vacancies generated unexpectedly in CuO<sub><i>x</i></sub> enabled it to produce reactive oxygen species. After eight\ncycles of antimicrobial assays, the antimicrobial rates of bacteria\nwere higher than 99.5%, and those of fungi were greater than 98.3%.\nThe successful synthesis of antimicrobial fibers and the construction\nof multidimensional nanoscale structures through a simple postprocessing\nmethod provide a new design mentality for antimicrobial functionalization\nfor HEPA filters.